The field of this invention relates to an apparatus for filling or circulating fluids while inserting tubulars into or removing them from a wellbore and for recovery of fluids displaced when running tubulars into the wellbore. The field of this invention also relates to an apparatus for controlling a well.
When tubulars are being run into or pulled from a wellbore, it is often necessary to fill the tubular, take returns from the tubular or circulate fluid through the tubular. This requires that the pipe be threaded to a circulation system or the use of a device for filling or circulating a wellbore. Previous devices for filling and circulating the wellbore are firmly attached to the traveling block or top drive. In either case a very precise spacing is required of the seal assembly relative to the tubular and elevators. In the case where slip-type elevators are used, the spacing of the seal could be such that when the elevators were near the upset of the tubular, the seal could be out of the tubular. When required, the slips at the rig floor must be set on the tubular and the traveling block or top drive lowered in order to move the seal into sealing engagement with the tubular. This required that the running or pulling of the tubular stop until the slips were set at the rig floor and the seal engagement be made. This is not desirable when a well kick occurs or fluid is overflowing from the tubular.
In the case where xe2x80x9cside doorxe2x80x9d or latching elevators are used, the spacing of the seal system is very critical and the seal of previous devices must be engaged in the tubular prior to latching the elevators below the upset portion of the tubular. This requires that the seal be engaged in the tubular at all times that the elevators are latched on the tubular in order to facilitate circulation of fluids. When tubulars are racked back in the derrick such as multiple sections of drill pipe, it would be very time-consuming if not impossible to insert the seal into the tubular prior to latching the elevators. This is true either on automated pipe handling rigs or rigs with the top of the tubular far above the derrick man. There is a disadvantage in having the seal engaged in the tubular at all times that the elevators are latched. In these cases the top of the tubular can not be accessed as when it is necessary to place a safety valve into the upper tubular section or in, if a high-pressure line was to be attached to the tubular and the tubular moved after making the connection. All previous devices had to be xe2x80x9claid downxe2x80x9d to allow a threaded connection to be made to the tubular since these devices are in the way of placing a new device into the upper tubular connection.
It will be seen that the invention described in this application, with its rapidly extending and retracting features and the ability to easily threadedly connect to or disconnect from the tubular or seal to or unseal from the tubular, is very advantageous. This is particularly true during any of the operations involving well control, drilling, completion, work-over, fishing or other activities requiring the running and pulling the tubular. This invention also eliminates all of the disadvantages of the prior art devices.
When tubular such as casing is run into a wellbore it is often advantageous to fill each successive section with mud as it is advanced into the wellbore. As the casing or tubing advances into the wellbore, a certain amount of mud is displaced. If the tubular is open-ended at the bottom advancement of the tubular into the wellbore will force mud from the wellbore into the tubular and annulus. If the open ended tubular is installed in a wellbore having fairly tight clearances with the tubular, rapid advancement of the tubular into the wellbore will result in significant flow of mud through the tubular and onto the rig floor area. In addition when fluid is flowing from the tubular it is difficult to determine whether the flow is from decompression of the fluid column or flow from a formation in the well bore. If it is flow from a formation it is advantageous to provide a method of rapidly sealing on the tubular or making a threaded connection to the tubular to control the well.
When attempting to pull the tubular from the wellbore, resistance to extraction can be experienced and consequently xe2x80x9cswabbing inxe2x80x9d and ultimate loss of control of the well could occur. It is obvious that it would be advantageous to add fluid to the tubular to maintain sufficient hydrostatic pressure in the wellbore while extracting the tubular.
Thus, there arises a need for a device that will simply allow capturing of any displaced returns during advancement of the tubular or, alternatively, allow rapid filling of the tubular and wellbore for insertion into or extraction out of the wellbore.
As the tubular is advanced into the wellbore pressure is built up in the well and is relieved only by flowing to the surface or being forced into the formation. Since the well fluids are generally compressible fluid will continue to flow from the well after the tubular string is set in the slips at the rig floor. For this reason it is desirable to provide a method of relieving this pressure at the rig floor prior to retracting the seal of the present invention.
Another advantage of the present invention is to be able to handle sudden surges of pressure from the formation. In these situations, it is desirable to be able to secure a valve in the tubular string connected to the mud supply so that the pressure surge from the wellbore can be contained. Thus, an objective of the present invention is to allow rapid connection or release from a tubular being added or removed to or from a tubular string during insertion or removal operations.
In addition it is another object of the present invention to provide an integral safety valve that is can be manually operated so as to shut-in the well and thereafter allows control of the well by applying fluid behind the valve. In addition an objective is to provide a safety valve that is not operated until required to assure its pressure holding integrity.
It is yet another object of the present invention to allow a system of rapid connection and disconnection to the tubular for filling or capturing of returns with minimal or no spillage in the rig floor area.
It is another object of the present invention to allow circulation of fluid at any time during rig operations for conditioning the wellbore, fluid system, or controlling a kick.
It is another object of the present invention to provide a mud saver valve to prevent fluid from escaping the tool when the tool is disconnected from the tubular without having to operate the manually operated valve.
In addition it is desirable to provide a very large flow path through the mud saver valve to prevent erosion. In addition it is also desirable to provide a large return flow path through the mud saver valve to allow fluid to flow from the tubular with little restriction.
Another object of the present invention is to provide a singular control system for extending and retracting the seal unit of the present invention.
In some circumstances when control of the well requires the tubulars to be run into the well under pressure a safety valve is attached to the tubular and is run into the well along with additional tubulars. Therefore it is another objective of the present invention to provide a means for removal of the mud saver valve and the outer components of the apparatus and the attachment of the integral safety valve to the tubulars to allow the tubulars to be run into the well.
In some circumstances the outside of the tubular connection will become damaged due to tong marks of other damage caused by handling or normal wear while running the tubular in and out of the well that will prevent sealing on these surfaces. In most tubular connections there are closely controlled dimensional tolerance surfaces inside the female connection and not part of the tubular body immediately above and or below the threaded portion of the tool joint or coupling. These surfaces are excellent alternative sealing surfaces not subject to damage as are external surfaces of tubular connections. Use of these surfaces also eliminates the flow restrictions of the tubular body found in previous devices that require a seal to be inserted into the tubular body. Therefore it is another objective of the present invention to provide a means of sealing at these surfaces and to provide the largest possible non-restricting flow area.
Prior systems relating to techniques for filling casing are disclosed in U.S. Pat. Nos. 5,152,554; 5,191,939; 5,249,629; 5,282,653; 5,413,171; 5,441,310; 5,501,280 as well as U.S. Pat. No. 5,735,348.
Other prior art for changing the spacing of devices above the tubulars are disclosed in U.S. Pat. No. 5,577,566 and 5,918,673.
A system for capturing displaced fluid or pumping fluid through tubulars being run into or out of the wellbore is described. Embodiments are supported by a traveling block and top drive unit with telescoping features to rapidly seal over a tubular to connect the tubular to a mud system. Alternative sealing arrangements for sealing inside the tubular connection are also disclosed. These alternate sealing arrangements also provide flow areas larger than the tubular body since no portion of these arrangements enter the tubular body. All of the sealing arrangements provide a biased area whereby any internal pressure in the invention forces the seals into more intimate contact with their mating seal surfaces. A mudsaver valve having a large flow capacity is described to keep fluid from spilling when the apparatus is removed from the tubular. This mudsaver valve also provides for pumping of fluid into the tubular or flow of fluid from the tubular to the mud system prior to removing the apparatus from the tubular. In these embodiments, the apparatus can be placed in threaded sealing contact with the tubular and can incorporate a safety valve that can be manually closed in the event of a well kick. In another embodiment, a singular control input accomplishes operation of the apparatus to extend or retract the telescoping feature. Also illustrated is a drain valve that provides a method of completely removing all fluid pressure from within the apparatus prior to removing the apparatus from the tubular. The drain system also provides a means of disposing of the excess fluid away from the rig floor where spillage is a danger to the personnel or environment. The drain system can also be connected to a scavenger system that is intended as a vacuum system for removal of spillage. Connection to this system eliminates all possible spillage and completely removes fluids from the tubular handling area.